ABSTRACT
Objective To evaluate the effects of limb ischemic preconditioning on intestinal injury and brain injury induced by hepatic ischemia?reperfusion(I∕R)in rats. Methods Healthy male Wistar rats, aged 6-8 weeks, weighing 200-250 g, were divided into 3 groups(n=16 each)using a random number table: sham operation group(Sham group), hepatic I∕R group(I∕R group)and limb ischemic preconditioning group(LIP group). In LIP group, the lower limb blood flow was blocked for 10 min with an elastic rubber tourniquet at the right groin followed by 30?min reperfusion through releasing the tourni?quet. Hepatic I∕R injury was induced by occlusion of the portal vein, hepatic artery and common bile duct for 30 min followed by reperfusion in I∕R and LIP groups. Eight rats in each group were selected at 6 h of reperfusion and samples from the cardiac apex were taken for determination of plasma concentrations of tumor necrosis factor?alpha(TNF?α)and interleukin?10(IL?10)by radioimmunoassay. Then the rats were sacrificed and the small intestine tissues and brain tissues were removed. Intestinal damage was as?sessed and scored according to Chiu. The activity of myeloperoxidase(MPO)in intestinal mucosa was de?tected by colorimetric method. The pathological changes of brain tissues were examined under a light micro?scope. The ultrastructure of brain tissues was observed under an electron microscope. Eight rats in each group were randomly selected at 6 h of reperfusion, and Evans blue(EB)2 mg∕kg was injected through the caudal vein over 1 min. Then the rats were sacrificed, brain tissues were removed for measurement of EB content, and the brain water content was calculated. Results Compared with Sham group, Chiu′s score and MPO activity in intestinal tissues were significantly increased, the brain water content and EB content were increased, and the concentrations of TNF?α and IL?10 in plasma were increased in I∕R group and LIP group(P <0.05). Compared with I∕R group, Chiu′s score and MPO activity in intestinal tissues were significantly decreased, the brain water content and EB content were decreased, and plasma IL?10 concentrations were increased(P <0.05), no significant change was found in plasma TNF?α concentra?tions(P>0.05), and the pathological changes of brain tissues were significantly attenuated in LIP group. Conclusion Limb ischemic preconditioning can attenuate intestinal injury and brain injury induced by he?patic I∕R, and the mechanism may be related to inhibiting systemic inflammatory responses of rats.
ABSTRACT
Objective To evaluate the effects of limb ischemic preconditioning (LIP) on the intestinal injury during release of hepatic portal occlusion (RHPO) in rats.Methods Thirty-six male Sprague-Dawley rats,aged 6-7 weeks,weighing 200-250 g,were randomly divided into 3 groups using a random number table:sham operation group (group S,n =12),RHPO group (n =39) and LIP+ RHPO group (n =20).Hepatic ischemia/ reperfusion was produced by occluding portal vein and hepatic artery for 30 min followed by 6 h reperfusion according to Pringle's method.LIP was produced by tourniquet occlusion of the right femoral artery and vein for 10 min followed by 24 h reperfusion before hepatic ischemia.The animals were sacrificed at 6 h after hepatic portal occlusion was released and the mucous membrane of small intestine was obtained for microscopic examination and for determination of malondialdehyde (MDA) content,superoxide dismutase (SOD) activity,myeloperoxidase (MPO)activity,total antioxidant capacity (T-AOC) and intercellular adhesion molecule-1 (ICAM-1) mRNA and protein expression.The degree of damage to intestinal mucous membrane was scored according to Chiu.Results Compared with group S,Chiu's score and levels of MDA and MPO were significantly increased,SOD activity and TAOC were decreased,and ICAM-1 mRNA and protein expression was up-regulated in group RHPO (P ＜ 0.05 or 0.01).Compared with group RHPO,Chiu's score and levels of MDA and MPO were significantly decreased,SOD activity and T-AOC were increased,and ICAM-1 mRNA expression was down-regulated in group LIP + RHPO (P ＜ 0.05).Conclusion LIP can alleviate the intestinal injury during RHPO in rats by enhancing the antioxidant function and down-regulating the expression of ICAM-1.